THYSANOPTERA OR THRIPS. 



233 



THYSANOPTERA. 



Thrips, or Black Fly. 



The Thripidm, or Black Fly, sometimes called Thunder-fly, 

 form a distinct order of insects, characterised by having 

 four thin, narrow, fringed wings and an imperfect suctorial 

 mouth. The metamorphosis is very slight. Several of them 

 are injurious to crops, and are equally obnoxious in green- 

 houses. Thripidffl are minute dark insects in their adult 

 state, and feed by suction, although the mandibles are repre- 

 sented by a pair of needle-like processes. One species, Thrips 

 cerealimn (fig. 118, 1 and 2), is often very harmful to com. 



Pig. 118.— Thrips. 



1, Female Thrips cerealium with wings closerl ; 4, with wings expantleil ; 2, 3, 5, 7, 

 nat. size ; 6, larva of T, miniitissima : 8, T. viintUistiima. (Curtis.) 



The larva and pupa are similar to the adult, but are smaller 

 and differ in colour ; the larva is deep yellow, with two dusky 

 spots on the thorax ; the pupa is pale yellow, with white legs, 

 antennae, and wing-cases. The eyes and ocelli are reddish. 

 The adult is deep black and winged in the female, apterous in 

 the male. The legs are paler, and the two-jointed tarsi terminate 

 in a little gland, hence they are sometimes called " Bladder-feet.'' 

 The Corn Thrips is about | of a line long. This pest feeds off 



